Direct rectifying process for the production of pure alcohol



May 30, 1933. E, RICARD r AL A 1,912,010

DIRECT RECTIFYING PROCESS FOR THE PRODUCTION OF PURE ALCOHOL Filed May 19, 1930 2 Sheets-Sheet 2 Patented May 30,1933

UNITED STATES.

ATENT OFFICE ELOI RICABD .A ND HENRI MARTIN GUINOT, OF MELLE, FRANCE, ASSIGNORS TO SOCIETE ANONYME DES DISTTILLERIES DES DEUX-SEVRESfOF MELLE, FRANCE, A CORPORIT.

TION OF FRANCE manor nncrrryme rnocnss FOR THE rnonvcrrron or 'ruan ALcofioL Application filed May 19, 1930, Serial No. 453,524, and in Austria August 2, 1929.

It is known that there are many types of rectifyin apparatus which make it posslble to treat ermented worts, wines, or weak alcoholic dilutions, in order to extract therefrom pure alcohol.

However, in spite of the great diversity of the proposed systems, modern apparatus have all in common the fact that they are based on the two following fundamental principles Y 1. They first carry out a purification, called low degree purification, in order to eliminate the volatile impurities. Said impurities are obtained diluted in alcohol at the top of a column generally called puri fying' column, wherefore their name of.

head products.

2. They next carry out a purificatlon, called high degree purification in a rectifying column in order to separate the heavy impurities called fusel oils; the latter are extracted mixed with a relatively important proportion of alcohol in an intermediate part of the concentrating column, generallyat a point where the strength of the alcohol on the plates reaches 40 to 70 GL. where-v fore ,their name of tailings. All writers on the question concur in insisting on the absolute necessity of producing, during that step, an alcohol having a very great strength, 96, 5 GL., for instance; otherwise, the oils ascend in the column together with the ure alcohol,and give it a disagreeable smel However high the strength of alcohol is maintained, this purification is but more or less perfect, and it is never complete. y

In order to obtain the high degree to which this purification must be carried out,

it is necessary to use columns comprising a great number of plates, or combinations of I complicated apparatus, and in most cases,

to spendmuch more steam than would be necessary for extracting all the alcoholfrom the wort which is treated. Lastly, it is admitted that the apparatus which does not comprise both methods of urification, as above mentioned, can give ut roughly purified alcohol.

The present invention relates to a new need of, bringing the-alcohol to' a great strength as in the ordinary rectification.

In the present specification, the use of the terms head products and tailings will be systematically avoided. Y

This invention, indeed, is based on principles which are opposed to all that has been said hitherto, on account of the fact that thepurification at a low degree is effected with very low'percentages of alcohol, preferably below 20 Gay-Lussac, and that, instead of trying to eliminate the volatile impurities, one eliminates entirely and easily the water insoluble impurities, including a part of the heavy impurities. For that purpose use is made of the fact that the heavy impurities can, in certain cases, behave like .volatile products, a fact that had been discovered for some of them, such as the ethyl insovalerianate, but in different conditions; and hitherto, nobody had ever thought of systematically utilizin' said property.

Said low degree puri cation is also characterized by the fact that the operation is effected by vaporizing a very small part of the feed liquids, not by acting on the whole of the alcoholic vapours of the worts, and that any concentration of the alcohol is systematically avoided, on account of the absence of concentrating plates and of any retrograding circulation, while, previously, the purification at a low degree was always effected simultaneously with a certain concentration of the alcohol, which sometimes was even provoked.

In a second part of the apparatus, the al- .cohol is concentrated by distillation, and, at the same time, the purification in respect.

It is heated to the boiling point before it enters said column, or during its passage through it, by any suitable means. A small part of the liquid that passes through said column is vaporized.

The vapors which are produced are directly condensed or before being, condensed, they are passed through a small accessory column comprising a small number of plates which are sprinkled on their upper faces with a current of very hot water. The liquid that is obtained through condensation of said vapours is substantially free from alcohol, and contains the whole of the heavy products called fusel oils, together witha part of the volatile impurities. Said liquid is not sent back into the column; it is decanted, if necessary, and stored with a view to extract subsequently the heavy esters and the higher alcohols. I

The whole of the column, thev accessory small column,-and the condenser, arranged for the purification of the feed liquid before the latter is submitted to the distillation of the alcohol, is called hydroselector.

The fermented worts,'wines, or weak alcoholic solutions flowing from the bottom of the hydroselector, contain, in addition to their original .alcohol, the remainder of the volatile impurities. 'They enter a distilling column in order that the alcohol be distilled, and the remaining volatile impurities elim-' inated by the ordinary means.

In fact, the process according to the invention is not characterized by the terminal operations of distillation and purification, but by their combination with the pre-purifi cation of the fermented wort, wine, or wea alcoholic dilution in the hydroselector apparatus in order to remove the whole of the water insoluble im urities and a part of the volatile water inso uble impurities.

That combination has a direct influence on the results obtained, not only through the quality of the alcohol, which is obtained in a strictly fpure state, andnot only through the yield 0 *the operation, since about 98% of the alcohol presentin the fermented wort, wine or weak alcoholic dilution is recovered, but also because the extraction of the last volatile impurities does not require the obtaining of an alcohol of a very great strength. It is therefore not necessary that the istilling columnshould'have a great number of concentrating plates, and consequentl said column consumes but the quantlty o I vapour which is necessaryfor the extraction of alcohol from the wort.

It should well understood that the part of the weak alcoholic liquid must' be vaporized must be very small, approximating 0.5% of the wort that is treated. That protity of the initial liquid that is treated.

Such a vaporization is indeed suflicient in fication of alcohol, it is not necessary, in that first o ration, to vaporize such a quantity of liquid that the whole of the tail impurities be drivenout together with the whole of the head impurities.

There is no roportional relation between the quantity of liquid that is vaporized and the initial percentage of alcohol in the liquid that has been treated.

Concerning the operating mode of the process in which an abundant dilution is used, it has been found that said sprinkling must be such that the vapours are really washed by water.

Said operation must not be confused with the known operation which consists in making addition of fermented worts or hot water the sole purpose of which is to prevent the percentage of alcohol from increasing.

There are, between these two operations, essential differences which may serve to characterize the invention.

In the already known process:

1. The alcoholic concentrations are the same on the plates where the raw materials are fed as on the plates where water arrives.

2. The temperatures are the same on these plates.

3. The vapours that arise from the plate where the arrival of water takes place, carry away alcohol, for their percentage of alk cohol is much 'higher than that of the liq- 6. There is an accumulation of impurities on the plates located in the vicinity of the water inlet. j

In the process according to the present invention, on the contrary I 1. The alcoholic concentration on the \higher plate, where water arrives is zero,

or substantially so, the washing action being supposed to be suflicient to bring back the ethylic alcohol toward the column 'bottom.

2. The temperature on the late where water arrives. is noticeably higher than the temperature on the plate where the feeding of raw material takes place, a paradoxical enough fact when compared with the ordi-.

nary condition of func tioning in the colportion may be slightly difierent, but, innmns practice, it not superior to 3% of the quan- 3. The vapours that arise from the plate of the process.

where water arrives contain substantially into column A. If the required temperature but products which are .insoluble in water. is not reached in 1, the heating is completed -Aftersaid' vapours are condensed, the conby introducing, through pipe 3, vapour into densate is decanted, which is a characteristic the bqttom of column A or in any other way. (Pipe 3 may take heating vapour from the 4. The washing water cannot be at any bottom of column Dor preferably in a zone temperature. It must be at a high enough higher than the bottom as shown'in Figure temperature for not stopping the azeotropic 2). A small outflow of vapours, correspondmixtures formed by bodies that are insoling to 0.5% of theweight of the treated: uble or not very soluble in water. Said wort, is regulated through valve 4. Said vatemperature must have been reached before pours are condensed in condenser C; the

the entrance of said water in the column so resulting liquid flows through pipe 5, and

that it be not necessary to reheat it artificialcontains the whole of the .water insoluble ly through an addition of calories coming impurities and a small part of the most from the bottom of the column which would volatile water soluble impurities. resultin a concentration of the alcohol on Instead of sending the vapours directly the upper plates, as it is well known. As a into condenser C, it is generally preferable rule, said temperature generally approxito send them through a pipe 13 into a small mates 95 C. column E (Figure 2) through which they 5. It is not'possible to use, instead of wapass from bottom to top. From said column ter, fermented wort or an alcoholic'liquid, B they are'sent to condense in condenser C, even very weak, for,such a liquid, if it can without being submitted to a backward cir prevent an increase of the alcoholic strength culation. Column B is fed, at its top, with on the plates,'cannot, on the other hand, efa small current of very hot water coming fect the washing of the vapours, on account from tank H through pipe 6, said water corof the fact that said liquid can itself emit responding to about 5% of the'treated Wort, vapours the alcoholic content of which is and passing through pipe 7 into column A. substantially the same as the alcoholic con- The quantity of vapours produced in A, tent of the vapours to be washed. and the quantity of water passing through 6. There is no accumulation of impurities B, may vary in large proportions, the indiin any part Of the appar t s, On account of cations given in the present example permitthe fact that the vapours of the azeotropic ting to effect a good purification. mixtures formed by the impurities pass The purified wort flowing from hydrosethrough the zone of water sprinkling withlector A is delivered through pipe 8 into out being stopped, and are sent to the condistilling column'D, where it is distilledin denser where from they are discharged, and the ordinary way. The alcoholic vapours are never sent back into the column. pass through pipe 14 andare condensed in If the. operation is effected according to condenser E. A part is sent back to column the indications of the present specification, D through pipe 9 and the other part is exit will be recognized that, owing to the hytracted through pipe 10 and consists of the droselector, the whole of the impurities water soluble impurities. The pure alcohol which are insoluble or not very soluble in is extracted through pipe 11, some plates bewater is eliminated and in addition some low the top of the column. very volatile impurities are removed. The impurities which'are to be removed The alcohol coming from the hydroselecby the present process are those which are tor contains accordingly most of the imcommonly encountered in alcoholic worts v purities which are soluble in water. Said and the like impurities are easily separated during" the secondpart .of the operation which consists purities which are insoluble in water, whatin distilling and concentrating the alcohol ever their volatility or boiling point. 'Inand at the same time purifying it by known cluded in these are the heavy impurities. methods. The following are given as examples of wa- The following examples, together with the ter insoluble impurities which may be reappended drawings, will serve to illustratemoved at this stage of the process: normal the invention. propyl alcohol, isobutyl alcohol, isoamyl- Figure 1 is a diagrammatic View of an apparatus according to the invention.

Figure 2 shows a modified form of said apparatus.

The material is a beet wort containing 5% of alcohol.' Said wort'flows from tank M (Figure 1) through heater '1, heated,in the known way, by distillation roducts coming from distilling column D t rough pipe 15, The heated wort is then sent through pipe? In the hydroselector are removed all imcentration of the alcohol, the remainder of the volatile, water-soluble .impurities, together withcertain heavy water-soluble impurities such as glycerine, are removed.

The alcohol extracted throughpipe 11 is generally very pure, from a chemical and organoleptic point of view. But, if for some particular reason, a lastpurification was necessary, it could be submitted to any complementary treatment. For instance it could be submitted to a very weak partial boiling in a small column G wherefrom the vapours would go, through pipe 12 into condenser E, and absolutely pure alcohol would be extracted through pipe 13.

Likewise, if it is wanted to obtain the head impurities, extracted in 10, in a more condensed form, they may be concentrated by the ordinary means.

Instead of feeding column A with a weak alcoholic liquid, it is'possible, without departing from the spirit of the invention, to feed said column with a strong alcoholic liquid, which is changed into a,weak dilution by increasing the quantity of hot water that is delivered into column A through column The above described apparatus could also be used for treating methyl alcohol aqueous solutions of any kinds. It may be used in whole or in part, if need be, at a pressure different from atmospheric pressure, in or-. der to facilitate heat'recuperation, .or for any other purpose.

Gay-Lussac degrees referred to in this specification are the expression of the percentage .of alcohol by volume in the solution.

What we claim is 1. Process for obtaining pure alcohol from v weak alcoholic liquids, which comprises first j vaporizing a :fraction of said alcoholic liquids not exceeding three percent. of the substantially without concentration of a ooholic vapors, so as to remove the water-insoluble impurities, and subsequently distilling and concentrating the liquids so as to remove the remaining impurities.

2; Process for obtaining purealcohol from weak alcoholis liquids, which comprises first vaporizing a fraction of said alcoholic -li uids notexceeding three -per cent. of the w ole mass while pouring thereon a suflicient quantity of sufliciently hot water to avoid any substantial concentration of alcoholic vapors and to permit removal of the water-insoluble impurities while preventing the passage of alcohol vapor, re-

- moving the vapors containing said impurities and subsequentlydistilling and concentrating the liquids, so as to remove the re- -maining impurities.

3. Process for obtaining pure, alcohol from weak alcoholic liquids, WhlCh comprises first vaporizing a fraction of said alcoholic liquids not exceeding three per cent. of the whole mass while pouring thereon a sufiicient quantity of sufliciently hot water to and condensing the same, removing the condensate resulting therefrom, and subsequently distilling and concentrating the liquids'so as to remove the remaining impurities.

4. Process for obtaining pure alcohol from weak alcoholic liquids, which comprises first heating said liquids, vaporizing a portion not exceeding three per cent. of the whole mass, and removing these impure vapors, any substantial concentration of alcoholic vapors being avoided at this stage of the process, and then distilling and concentrating the result-ing liquids so as to remove the remaining impurities.

In testimony whereof we have signed this specification.

ELOI RIOARD. HENRI MARTIN GUINOT. 

